Population dynamics of Viola pedata on deep sandy soils in a fragmented and degraded landscape

Abstract

Habitat destruction and subsequent fragmentation can have a multitude of effects on all levels of ecological organization. We investigated the population dynamics of Viola pedata L. (bird-foot violet [Violaceae]) in a highly fragmented ecoregion, the tallgrass prairie of central North America. We monitored V. pedata density in a small population on deep sandy soils in central Illinois for 12 y and conducted a 3-y experiment to observe the effects on V. pedata of clipping aboveground vegetation and removing leaf litter. Our results indicate the abundance of V. pedata is highest in partial shade and is affected by burning for only 1 to 2 y. Furthermore, our results suggest V. pedata is restricted to dry, open prairies because low light availability near the ground surface in mesic sites excludes the short-statured V. pedata. At our study site, we hypothesize poor seed production reduces the ability of the population to attract ants as secondary seed dispersers and thus decreases seed germination, seedling establishment, and colonization of unoccupied but suitable habitat.